DESCRIPTION: We propose to study back disorders among high risk carpenters, building upon prior research utilizing a historical cohort of union carpenters in Washington State. The existing cohort of 16,215 carpenters followed from 1989-98 will be updated to include new entries through 2003. Workers' compensation (WC) and private health insurance claims will be updated for the existing cohort and obtained for new entries through the Washington Dept of Labor and Industries and the Carpenters' Trusts of Western Washington, respectively. The union will provide hours worked by person and a marker of eligibility for union insurance coverage by month. The data, linked on an individual basis, will provide a comprehensive picture of the WC experience of this historical cohort, their health care utilization through both WC and their private union insurance, and measures of time at risk. Claims and costs for work-related back disorders over the15 year period will be identified, as will those for treatment through private insurance. Incident and recurrent WC claims will be defined and rates calculated. Using survival techniques we will explore whether the risk of recurrence varies for different definitions of an incident case based on time off work, ICD9 diagnoses, nature or mechanism of injury. Time window analyses will be used to determine whether there are periods of time when risk of recurrence is greater following return to work. Using a case-control approach, back injuries that result in prolonged loss of time from work will be contrasted with those resulting in more rapid return to work. Analyses of utilization and costs will define resource use for back injuries over time across both payment systems. Finally, a series of focus groups will be conducted to inform results and explore issues related to return to work following injury not available in the administrative data. This work will provide a better understanding of the magnitude, nature, and societal burden of back disorders among construction carpenters, a group particularly challenging to study. The analyses will provide important information on the more costly work-related injuries and risk factors for recurrent vs. initial injuries, and insight into the interplay of care across workers' compensation and private insurance coverage. The project addresses a number of areas of expressed interest to NIOSH including construction workers, back disorders, surveillance methods and health services research. [unreadable] [unreadable]